The present invention relates to golf balls and more particularly, the invention is directed to a progressive performance golf ball having a high moment of inertia sub-assembly.
The spin rate of golf balls is the end result of many variables, one of which is the distribution of the density or specific gravity within the ball. Spin rate is an important characteristic of golf balls for both skilled and recreational golfers. High spin rate allows the more skilled players, such as PGA professionals and low handicapped players, to maximize control of the golf ball. A high spin rate golf ball is advantageous for an approach shot to the green. The ability to produce and control back spin to stop the ball on the green and side spin to draw or fade the ball substantially improves the player""s control over the ball. Hence, the more skilled players generally prefer a golf ball that exhibits high spin rate.
On the other hand, recreational players who cannot intentionally control the spin of the ball generally do not prefer a high spin rate golf ball. For these players, slicing and hooking are the more immediate obstacles. When a club head strikes a ball, an unintentional side spin is often imparted to the ball, which sends the ball off its intended course. The side spin reduces the player""s control over the ball, as well as the distance the ball will travel. A golf ball that spins less tends not to drift off-line erratically if the shot is not hit squarely off the club face. The low spin ball will not cure the hook or the slice, but will reduce the adverse effects of the side spin. Hence, recreational players prefer a golf ball that exhibits low spin rate.
Reallocating the density or specific gravity of the various layers or mantles in the ball is an important means of controlling the spin rate of golf balls. In some instances, the weight from the outer portions of the ball is redistributed to the center of the ball to decrease the moment of inertia thereby increasing the spin rate. For example, U.S. Pat. No. 4,625,964 discloses a golf ball with a reduced moment of inertia having a core with specific gravity of at least 1.50 and a diameter of less than 32 mm and an intermediate layer of lower specific gravity between the core and the cover. U.S. Pat. No. 5,104,126 discloses a ball with a dense inner core having a specific gravity of at least 1.25 encapsulated by a lower density syntactic foam composition. U.S. Pat. No. 5,048,838 discloses another golf ball with a dense inner core having a diameter in the range of 15-25 mm with a specific gravity of 1.2 to 4.0 and an outer layer with a specific gravity of 0.1 to 3.0 less than the specific gravity of the inner core. U.S. Pat. No. 5,482,285 discloses another golf ball with reduced moment of inertia by reducing the specific gravity of an outer core to 0.2 to 1.0.
In other instances, the weight from the inner portion of the ball is redistributed outward to increase the moment of inertia thereby decreasing the spin rate. U.S. Pat. No. 6,120,393 discloses a golf ball with a hollow inner core with one or more resilient outer layers, thereby giving the ball a soft core, and a hard cover. U.S. Pat. No. 6,142,887 discloses a high moment of inertia golf ball comprising one or more mantle layers made from metals, ceramic or composite materials, and a polymeric spherical substrate disposed inwardly from the mantle layers. U.S. Pat. No. 705,359 discloses a golf ball having a perforated metal shell positioned immediately interior to the outer cover. U.S. Pat. No. 5,984,806 discloses perimeter weighted golf ball, wherein the weights are visible on the surface of the golf ball. On the other hand, the weight of the ball can also be distributed outward by using a hollow, cellular or other low specific gravity core materials, as disclosed in U.S. Pat. Nos. 6,193,618 B1 and 5,823,889, among others.
These and other references disclose specific examples of high and low spin rate balls, but none of these references employ the selective variation of the ball""s moment of inertia to create a progressive performance ball, which exhibits low spin when struck by a driver and high spin when struck by a wedge. Hence, there remains a need in the art for an improved progressive performance golf ball.
The present invention is directed to a golf ball with a controlled moment of inertia.
The present invention is also directed to a progressive performance golf ball with a controlled moment of inertia.
The present invention is preferably directed to a ball comprising an intermediate layer covering a core and a cover encasing the intermediate layer. The intermediate layer preferably comprises a non-continuous layer having a specific gravity of greater than 1.2 and a thickness from about 0.025 mm to 1.27 mm. The intermediate layer is preferably positioned at a distance radially outside of the centroid radius. The intermediate layer is preferably positioned at a distance ranging from about 0.76 mm to 2.8 mm from the outer surface of the golf ball.
In accordance to another aspect of the invention, the specific gravity of the non-continuous layer is greater than 1.5, more preferably greater than 2.0. The thickness of the non-continuous layer may also range from 0.127 mm to 0.76 mm, and more preferably from 0.25 mm to 0.5 mm.
In accordance to another aspect of the present invention, the intermediate layer may also comprise a thin dense layer having a specific gravity of greater than 1.2 and positioned proximate to the non-continuous layer. Additionally, the intermediate layer may also comprise a second non-continuous layer.
In accordance to another aspect of the invention, the golf ball comprises an intermediate member and a non-continuous member, and the intermediate member is located proximate to the non-continuous member.
The core preferably has a specific gravity of less than 1.1, and more preferably less than 1.0, and even more preferably less than 0.9. Additionally, the core is preferably foamed to reduce its specific gravity. Alternatively, the core may include fillers, hollow spheres or the like to reduce the specific gravity. The cover preferably has a hardness of less than 65 Shore D, more preferably between about 30 and about 60, more preferably between about 35 and about 50 and most preferably between about 40 and about 45. The cover is preferably made from a thermoset or thermoplastic polyurethane, an ionomer, a metallocene or other single site catalyzed polymer. The cover preferably has a thickness of less than 1.27 mm, more preferably between about 0.51 mm and about 1.02 mm, and most preferably about 0.76 mm.
Preferably, the non-continuous layer covers at least 10% of the surface area of an adjacent layer, more preferably at least about 25% and most preferably at least about 50%.
The present invention is also preferably directed to a ball comprising a core, an intermediate layer and a cover wherein the weight or mass of the ball is allocated outwardly to form a high moment of inertia and wherein the cover is made from a soft material having a hardness of 65 (shore D) or less. The moment of inertia of the ball is preferably greater than 0.46 ozxc2x7inch2, more preferably 0.50 ozxc2x7inch2, and most preferably 0.575 ozxc2x7inch2. Similar to the embodiment discussed above, the intermediate layer may comprise a non-continuous layer having a high specific gravity. It may also comprise a thin dense layer and/or a second non-continuous layer. The core preferably has a low specific and is preferably foamed. The specific gravities, locations, thicknesses, hardness and surface areas discussed above relating to the individual layers of the inventive golf ball are equally applicable to this embodiment.